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package org.apache.juneau.rest.vars;

import org.apache.juneau.rest.*;
import org.apache.juneau.rest.annotation.*;
import org.apache.juneau.rest.widget.*;
import org.apache.juneau.svl.*;

/**
 * HTML widget variable resolver.
 * 
 * <p>
 * The format for this var is <js>"$W{widgetName}"</js>.
 * 
 * <p>
 * Widgets are simple class that produce some sort of string based on a passed-in HTTP request.
 * 
 * <p>
 * They're registered via the following mechanisms:
 * <ul>
 * 	<li>{@link HtmlDoc#widgets() @HtmlDoc.widgets()}
 * </ul>
 * 
 * <h5 class='section'>See Also:</h5>
 * <ul>
 * 	<li class='link'><a class="doclink" href="../../../../../overview-summary.html#juneau-rest-server.SvlVariables">Overview &gt; juneau-rest-server &gt; SVL Variables</a>
 * </ul>
 */
public class WidgetVar extends SimpleVar {

	/**
	 * The name of the session or context object that identifies the {@link RestRequest} object.
	 */
	private static final String SESSION_req = "req";

	/**
	 * The name of this variable.
	 */
	public static final String NAME = "W";

	/**
	 * Constructor.
	 */
	public WidgetVar() {
		super(NAME);
	}

	@Override /* Parameter */
	public String resolve(VarResolverSession session, String key) throws Exception {
		RestRequest req = session.getSessionObject(RestRequest.class, SESSION_req);
		boolean isScript = false, isStyle = false;

		if (key.endsWith(".script")) {
			key = key.substring(0, key.length() - 7);
			isScript = true;
		}

		if (key.endsWith(".style")) {
			key = key.substring(0, key.length() - 6);
			isStyle = true;
		}

		Widget w = req.getWidgets().get(key);
		if (w == null)
			return "unknown-widget-"+key;

		if (isScript)
			return w.getScript(req);
		if (isStyle)
			return w.getStyle(req);
		return w.getHtml(req);
	}
}